It is known from EP 0 333 641 A1 that semiconductor electrolyte interfaces show photoelectrochemical properties which are similar to those of interfaces between a semiconductor and a metal in Schottky barriers. Semiconductors having a small distance between energy band and valence band in which charge carriers of the semiconductor are themselves photoelectrically excited by light, as is the case, for instance, with silicon, gallium arsenide and cadmium sulphide, are photocorrosively decomposed when illuminated by light when electrolytes are used. The sensitivity, i.e. the photochemical yield for visible light, i.e. sunlight, may be increased in that so-called chromophores, called also sensitizers or dyes, are chemically added or inserted on the surface of the semiconductor. The two functions of the light absorption and separation of charge carriers are separate in this photoelectrochemical system. The light absorption is taken over by chromophore in the surface region and the separation of the charge carriers takes place at the interface of the semiconductor and chromophore. For instance iodide, bromide or hydroquinone or other redox systems are suitable as electrolytes for such photoelectrochemical cells. As electrodes, there are used metal-oxide semiconductors. For this purpose particularly suitable are oxides of transition metals and elements of the third main group and of the fourth, fifth and sixth subgroups of the periodic table of elements, such as titanium, zirconium, hafnium, strontium, zinc, indium, yttrium, lanthanum, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and also oxides of zinc, iron, nickel or silver, perovskite or oxides of other metals of the second or third main groups or mixed oxides or oxide mixtures of these metals. The use of titanium dioxide as an electrode was shown to be advantageous. However, the efficiency of cells with electrodes of titanium dioxide is below the limit for economical operation.